Federal judges do not establish legal norms at will or on demand, but only when deciding cases that are justiciable, that is, appropriate for federal court decision. What makes a case justiciable is thus itself an important threshold question, because it determines whether a federal court will exercise its power to formulate and apply substantive law, rather than leaving the issues in the case to be resolved by political or other means. Hence, when the Supreme Court fashions the criteria of justiciability for itself and the lower federal courts, it effectively defines the nature and scope of the JUDICIAL POWER of the United States?the power to make decisions in accordance with law.
Most justiciability issues arise when litigants who are primarily motivated to vindicate public rights seek to contest the validity of government behavior, especially on constitutional grounds. Such public interest suits are usually
designed not so much to redress traditional personal grievances as to vindicate fundamental principles. Commonly the plaintiffs seek DECLARATORY JUDGMENTS or INJUNCTIONS to prevent government officials from carrying on objectionable practices that affect a wide segment of the population. These actions often test and illustrate the degree to which federal judges, particularly Supreme Court Justices, view their power of constitutional oversight as warranted only by the necessity to resolve traditional legal disputes or, instead, by a broader judicial mission to ensure government observance of the Constitution.
In demarcating the federal judicial function, the law of justiciability comprises a complex of subtle doctrines, including MOOTNESS, ADVISORY OPINIONS, and POLITICAL QUESTIONS, among others. The Supreme Court has derived that law from two sources: Article III, which limits federal judicial power to the decision of CASES AND CONTROVERSIES, and nonconstitutional "prudential" rules of the Court's own creation. Both Article III and the rules of prudence incorporate notions of the attributes or qualities of litigation that make the legal issues presented appropriate for judicial determination. The difference between the two is that if Congress wants to have the federal courts entertain public actions, it may override the Court's prudential barriers, but not the constitutional limits of "case" and "controversy."
Three primary, and often mutually reinforcing, conceptions of appropriateness shape...